What Are Terpenes, and Why Are They Important?

They are the volatile organic molecules secreted by flowers that shout “visit me!” to bees buzzing in your garden, they are the carriers of the pitch-perfect fragrance you catch when hiking through a pine forest, they are the carriers of that concentrated scent you inhale when the budtender whips the lid off a container of cannabis at a dispensary, and when herbalists tout the power of aromatherapy through “essential oils” from herbs and plants, they’re talking terpenes.

If there were such a thing as smell-o-vision, terpenes would be its A-list stars.

Terpenes scintillate (or scare) for a good reason. Many creatures navigate the world with their noses, and smell—along with its close cousin, taste—unite memory and learning centers of the brain. Even nasally challenged humans associate particular aromas with happy or comforting experiences, like that cinnamon thing mom had going for the holidays. However, they also can serve as warning signs: the stink in stink (or shield) bugs is their terpene reminder, “Don’t tread on me.”

Many terpenes are sticky and odorous to protect the plant that secretes them. Hence, the ubiquitous funky fragrance of cannabis sativa.

Upwards of 100 different terpenes have been identified in cannabis, and this aromatic advance guard can help you distinguish between various strains and their effects.

For instance, myrcene, which smells musky or earthy, is associated with a sedative effect; myrcene-heavy indica strains make you collapse in-da-couch. The citrusy scents of a limonene in a strain, on the other hand, signal an opportunity to brighten your mood and ’tude. Strains that contain the aptly named pinene are said to boost alertness and memory, and peppery caryophyllales often waft from CBD-heavy strains than can help ease a variety of ailments.

There are dozens more scents and sensibilities to explore. Just like a honeybee seeking out its favorite terpene-laden flower, you can sidestep confusing strain names and learn to select cannabis by associating the effect you’re after with the fragrance of the associated terpene. Let terpenes be your guideposts along the cannabis trail: They can help you follow your nose to your preferred destination. This cannabis color-wheel graphic from strain database Leafly associates the major terpene fragrances with their therapeutic and psychotropic effects.

And cannabis terpenes are not just another pretty or putrid smell. The psychoactive properties of tetrahydrocannabinol (THC) and anti-inflammatory qualities of cannabidiol (CBD) get all the credit for the potency of pot, but there is more emerging evidence for what is called the “entourage effect,” in which terpenes enable, enhance or moderate the high—and the health effects—of cannabis.

The landmark study Taming THC, published in the British Journal of Pharmacology, details how various terpenes can limit the downsides of cannabis (dopiness, anxiety) and amp the good (memory, concentration, joy). So if you’re not making terpenes part of your cannabis experience, you’re probably missing out on important information about brain and body benefits.

Which strains work best for you? There’s only one sure way to find out: See if they pass your sniff test.